Quality Assurance Flashcards
Factors to consider:
Staff Quality of materials Methods Reagents Pxn/physician satisfaction Financial cost Instruments Reporting of test results
Best possible service
Patient
Physician
Quality assurance
Involves the procedures of monitoring and evaluation of characteristics of the test system.
Quality Control
Only part of the quality assurance
Quality control
With predetermined assay value; with same matrix as pxn sample
Control
Reference material used to calibrate the instrument or prepare standard curves for manual assays
Primary std
Reference material in which analyte conc. has been ascertained by reference to primary std.
Secondary std
Preserved human or surrogate cell suspension whose hematology parameters have been determined by multireference lab and monitored daily by the distributor
Callibrator
Nearness or closeness of measurement to the true/actual value
Accuracy
Closeness of results obtained from repeated analysis of the sample.
Precision
Comparing result from the analysis of the sample from the result of the previous sample of the same analyte
Delta checks
Extent to which the method is able to maintain accuracy and precision overtime
Reliability
Range of values
Reference values
Most popular and well know measure of central tendency
Mean
A measure of dispersion of values from the mean.
Standard Deviation
Helps discribe the normal curve
Standard deviation
Measure the distribution range
Measure of precision
Standard deviation
A percentile expression of the mean and an index of precision
Coefficient of variation
A measure of relative magnitude of variability
Coefficient of variation
Proportion of patients with a disease who have a positive test result
Diagnostic sensitivity
Lowest amount of a substance that ca be detected accurately by a test method
Analytical sensitivity
Proportion of patients who are identified correctly by the test as not having the disease
Diagnostic specificity
How well a test method can detect a particular substance rather than similar ones
Analytical specificity
Proportion of patients without a disease who have a positive result compared with all patients who a positive test result
Positive predictive value
Proportions of patients w/o a disease who have a negative test result compared w/ all patients who have a negative test result
Negative predictive value
Errors within the test system or method
Affects the accuracy of a test method
Systematic error
Incorrect calibration procedures
Malfunctioning of components
Failure of some part of the testing process
Systematic error
Type of systematic error that the magnitude of error remains constant throughout the range of the test measurement
Constant error
Type of systematic error that the magnitude of error increases with the conc. of subs. being measures
Proportional error
Mistakes that occur without predictions/regularity
Random error
Instability of instrument
Change in temp
Operator variability
Affects boyh the accuracy but most is the precision of a test method
Random error
Sources of error
Pre-analytical
Analytical
Post-analytical
Misinterpreted physician test order
Pre-analytical
Pxn midentification
Pre-analytical
Errors in the actual testing of the specimens
Analytical
Incorrect result entry
Post-analytical
Incorrect pxn preparation
Pre-analytical
Failure to notify the physician of critical result
Post-analytical
Improper method of transport and handling
Pre-analytical
Miscommunication of report to nursing unit/physician
Post-analytical
Reports place in wrong patient chart
Post-analytical
Incorrect sampling technique
Pre-analytical
Improper collection container
Pre-analytical
Analysis of control samples along with the patients samples and statistical evaluation of results to determine the acceptability of the analytical run
Internal qc
Measure of precision overtime
Internal qc
Indicated the mean and 1sd, 2sd, 3sd on both sides of the mean
Levey Jennings control chart
Drift the values from one level of the control chart to another; either be sudden/gradual
Shift
Continuous movement of values in one direction
Trend
Samples will be used to the diff. lab by a reference lab. Proficiency testing programs
External QC
